python Lock、RLock

Lock: only acquire once, the next time to acquire the necessary release, or will cause deadlock

from threading import Lock

total = 0
lock = Lock()
def add():
    #1. dosomething1
    #2. io操作
    # 1. dosomething3
    global lock
    global total
    for i in range(1000000):
        lock.acquire()
        total += 1
        lock.release()


def desc():
    global total
    global lock
    for i in range(1000000):
        lock.acquire()
        total -= 1
        lock.release()

import threading
thread1 = threading.Thread(target=add)
thread2 = threading.Thread(target=desc)
thread1.start()
thread2.start()


#
thread1.join()
thread2.join()
print(total)

 

 

RLock

from Threading Import   RLOCK
 # RLOCK in the same thread inside, you can acquire continuously called multiple times, we must pay attention to the number and frequency of release to acquire equal 
Total = 0
lock = RLock()
def add():
    #1. dosomething1
    #2. io操作
    # 1. dosomething3
    global lock
    global total
    for i in range(1000000):
        lock.acquire()
        lock.acquire()
        total += 1
        lock.release()
        lock.release()


def desc():
    global total
    global lock
    for i in range(1000000):
        lock.acquire()
        total -= 1
        lock.release()

import threading
thread1 = threading.Thread(target=add)
thread2 = threading.Thread(target=desc)
thread1.start()
thread2.start()


#
thread1.join()
thread2.join()
print(total)